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Wang W, Yuan RK, Mitchell JF, Zitting KM, St Hilaire MA, Wyatt JK, Scheer FAJL, Wright KP, Brown EN, Ronda JM, Klerman EB, Duffy JF, Dijk DJ, Czeisler CA. Desynchronizing the sleep---wake cycle from circadian timing to assess their separate contributions to physiology and behaviour and to estimate intrinsic circadian period. Nat Protoc 2023; 18:579-603. [PMID: 36376588 DOI: 10.1038/s41596-022-00746-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 06/24/2022] [Indexed: 11/16/2022]
Abstract
Circadian clocks drive cyclic variations in many aspects of physiology, but some daily variations are evoked by periodic changes in the environment or sleep-wake state and associated behaviors, such as changes in posture, light levels, fasting or eating, rest or activity and social interactions; thus, it is often important to quantify the relative contributions of these factors. Yet, circadian rhythms and these evoked effects cannot be separated under typical 24-h day conditions, because circadian phase and the length of time awake or asleep co-vary. Nathaniel Kleitman's forced desynchrony (FD) protocol was designed to assess endogenous circadian rhythmicity and to separate circadian from evoked components of daily rhythms in multiple parameters. Under FD protocol conditions, light intensity is kept low to minimize its impact on the circadian pacemaker, and participants have sleep-wake state and associated behaviors scheduled to an imposed non-24-h cycle. The period of this imposed cycle, Τ, is chosen so that the circadian pacemaker cannot entrain to it and therefore continues to oscillate at its intrinsic period (τ, ~24.15 h), ensuring circadian components are separated from evoked components of daily rhythms. Here we provide detailed instructions and troubleshooting techniques on how to design, implement and analyze the data from an FD protocol. We provide two procedures: one with general guidance for designing an FD study and another with more precise instructions for replicating one of our previous FD studies. We discuss estimating circadian parameters and quantifying the separate contributions of circadian rhythmicity and the sleep-wake cycle, including statistical analysis procedures and an R package for conducting the non-orthogonal spectral analysis method that enables an accurate estimation of period, amplitude and phase.
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Affiliation(s)
- Wei Wang
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA, USA.
- Division of Sleep Medicine and Department of Medicine, Harvard Medical School, Boston, MA, USA.
| | - Robin K Yuan
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA, USA
- Division of Sleep Medicine and Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Jude F Mitchell
- Department of Brain and Cognitive Sciences, University of Rochester, Rochester, NY, USA
| | - Kirsi-Marja Zitting
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA, USA
- Division of Sleep Medicine and Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Melissa A St Hilaire
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA, USA
- Division of Sleep Medicine and Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - James K Wyatt
- Department of Psychiatry and Behavioral Sciences, Rush University Medical Center, Chicago, IL, USA
| | - Frank A J L Scheer
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA, USA
- Division of Sleep Medicine and Department of Medicine, Harvard Medical School, Boston, MA, USA
- Broad Institute, Cambridge, MA, USA
| | - Kenneth P Wright
- Sleep and Chronobiology Laboratory, Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, USA
| | - Emery N Brown
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, USA
- Institute for Medical Engineering and Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA, USA
- Institute for Data Systems and Society, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Joseph M Ronda
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA, USA
- Division of Sleep Medicine and Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Elizabeth B Klerman
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA, USA
- Division of Sleep Medicine and Department of Medicine, Harvard Medical School, Boston, MA, USA
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
| | - Jeanne F Duffy
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA, USA
- Division of Sleep Medicine and Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Derk-Jan Dijk
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
- UK Dementia Research Institute Care Research and Technology Centre, Imperial College London and the University of Surrey, Guildford, UK
| | - Charles A Czeisler
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA, USA
- Division of Sleep Medicine and Department of Medicine, Harvard Medical School, Boston, MA, USA
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Crowley SJ, Velez SL, Killen LG, Cvengros JA, Fogg LF, Eastman CI. Extending weeknight sleep of delayed adolescents using weekend morning bright light and evening time management. Sleep 2023; 46:zsac202. [PMID: 36006948 PMCID: PMC9832518 DOI: 10.1093/sleep/zsac202] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 07/13/2022] [Indexed: 01/14/2023] Open
Abstract
STUDY OBJECTIVES Shift sleep onset earlier and extend school-night sleep duration of adolescents. METHODS Forty-six adolescents (14.5-17.9 years; 24 females) with habitual short sleep (≤7 h) and late bedtimes (≥23:00) on school nights slept as usual for 2 weeks (baseline). Then, there were three weekends and two sets of five weekdays in between. Circadian phase (Dim Light Melatonin Onset, DLMO) was measured in the laboratory on the first and third weekend. On weekdays, the "Intervention" group gradually advanced school-night bedtime (1 h earlier than baseline during week 1; 2 h earlier than baseline during week 2). Individualized evening time management plans ("Sleep RouTeen") were developed to facilitate earlier bedtimes. On the second weekend, Intervention participants received bright light (~6000 lux; 2.5 h) on both mornings. A control group completed the first and third weekend but not the second. They slept as usual and had no evening time management plan. Weekday sleep onset time and duration were derived from actigraphy. RESULTS Dim light melatonin onset (DLMO) advanced more in the Intervention (0.6 ± 0.8 h) compared to the Control (-0.1 ± 0.8 h) group. By week 2, the Intervention group fell asleep 1.5 ± 0.7 h earlier and sleep duration increased by 1.2 ± 0.7 h; sleep did not systematically change in the Control group. CONCLUSIONS This multi-pronged circadian-based intervention effectively increased school-night sleep duration for adolescents reporting chronic sleep restriction. Adolescents with early circadian phases may only need a time management plan, whereas those with later phases probably need both time management and morning bright light. CLINICAL TRIALS Teen School-Night Sleep Extension: An Intervention Targeting the Circadian System (#NCT04087603): https://clinicaltrials.gov/ct2/show/NCT04087603.
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Affiliation(s)
- Stephanie J Crowley
- Biological Rhythms Research Laboratory, Department of Psychiatry and Behavioral Sciences, Rush University Medical Center, Chicago IL, USA
| | - Sabrina L Velez
- Biological Rhythms Research Laboratory, Department of Psychiatry and Behavioral Sciences, Rush University Medical Center, Chicago IL, USA
| | - Logan G Killen
- Biological Rhythms Research Laboratory, Department of Psychiatry and Behavioral Sciences, Rush University Medical Center, Chicago IL, USA
| | - Jamie A Cvengros
- Biological Rhythms Research Laboratory, Department of Psychiatry and Behavioral Sciences, Rush University Medical Center, Chicago IL, USA
| | - Louis F Fogg
- Biological Rhythms Research Laboratory, Department of Psychiatry and Behavioral Sciences, Rush University Medical Center, Chicago IL, USA
| | - Charmane I Eastman
- Biological Rhythms Research Laboratory, Department of Psychiatry and Behavioral Sciences, Rush University Medical Center, Chicago IL, USA
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